Film-maker Rebecca Thomas is the first to admit it. "I played the piano for 11 or 12 years and I thought I was going to be a pianist. Then I decided to draw and take photographs. Then, when I was in my senior year at high school, I was in an AV [audio visual] club.

"I was a total dork."

But Thomas's dork phase has paid off. At 27, her first feature, Electrick Children, has been attracting worldwide acclaim with a cast that includes Billy Zane – best known for Titanic – and Rory Culkin, brother of Macaulay Culkin. It has also pushed to the forefront its teen star Julia Garner.

Garner plays Rachel, a member of a fundamentalist Mormon family living in rural Utah. She is turning 15, wears old-fashioned modest clothes and there is limited technology. Rachel discovers a cassette tape and for the first time in her life hears rock music. Three months later she is pregnant and claims she had an immaculate conception from listening to the music. Her parents arrange a marriage but Rachel flees, with her brother in tow, to Las Vegas, the nearest city. There she hopes to find the man who sings on the tape and encounters the larger world for the first time.

Thomas is Mormon, but while the film is not based on her own experiences or those of people she knows, there is still a strong connection.

"I was raised Mormon and raised in Las Vegas but I never gambled or drank or any of those things in Las Vegas," says Thomas, now based in New York. "The plot has nothing to really do with me. The movie is this sort of take on fundamentalist Mormons.

"I grew up [as a] mainstream Mormon, so I grew up with TV and Nintendo and a stereo. But I definitely think that the experience Rachel goes through is something similar to my own experience. I had experiences that opened my eyes.

"My grandparents live in southern Utah, so Utah has always been special to me and Las Vegas is my home. I really wanted to show a different side to Las Vegas."

Before Electrick Children Thomas had made two short films. She wrote the script for the feature while studying film directing at Columbia University in New York.

Some of the ideas for featuring a fundamentalist Mormon settlement came from having worked on documentaries about the varied strands of Mormonism. She also set the film in southern Utah and Las Vegas for practical reasons – she was familiar with the area and knew people there whom she could get to work on it or act in it, so it would be much cheaper. "I was just going to use my friends and family."

But this is where Electrick Children goes in a direction Thomas had not even dreamed of. Her goal was to make the film on a "micro budget", she says. So she joined a "crowd funding" website like kickstarter.com, hoping to raise US$20,000 (NZ$24,000).

In the process, a copy of her script got into the hands of film producer Richard Neustadter. He was so impressed he raised US$1 million.

"Literally overnight, it went from a US$20,000 project to US$1 million and we were able to make a bigger project. It was one of these weird, dreamy miracles."

The bigger budget meant Thomas and the producers were able to lure more experienced actors. Thomas was already a fan of Culkin, who plays streetwise Las Vegas rocker Clyde. Zane plays Rachel's father Paul and Liam Aiken is her brother Mr Will.

Garner was cast a week before the frantic 24-day shoot began.

"I really wanted someone who was authentically 14 years old. I looked at a lot of girls and I cast a girl. But I couldn't find someone who was believably 14 and virginal. All the girls were a little bit too sexy.

"Julia Garner came as a recommendation from a friend at film school. She was stunning. She had that white skin and bright blue eyes. She was just an angel. And she's an angel in real life too. She is surprisingly pure.

"She gave a fantastic audition, but even just sitting down with her and talking with her was a revelation for me. She is a very bold but innocent person and I think that's what the film needed."

Thomas says shooting the film was a rite of passage. The fundamentalist Mormon settlement was shot "in the middle of nowhere" in an old ghost town that was used in Butch Cassidy and the Sundance Kid.

"It really brought the cast and crew together because of the weather. On day two lightning struck the middle of our set and we had to shut down, and every afternoon there was a huge rainstorm."

Thomas is determined to make more features. Like Electrick Children, her two new scripts shy away from the Hollywood norm. The first springs from her own experiences as a Mormon missionary in Japan for 18 months. "It was a really strange time but I learned Japanese and love Japanese culture and Japan. [The script] is a post-apocalyptic mermaid story set in Japan.

"The other project is a strange film noir set in New York City about a girl who falls in love with a girl who is running to be Miss New York. It's sort of bizarre."